Many spraying guns have been used widely for cleaning dust and dirt from a surface of an object, for watering, for spraying paint, and the like. The spraying guns remove dust and dirt by spraying a high pressure fluid, and perform watering and spraying paint with the use of a high pressure fluid mixed with water or other spraying liquid.
As shown in FIG. 1, which is a perspective view illustrating a spraying gun in a conventional prior art. The spraying gun A in which a high pressure gas G is conveyed from a control handle A1 is disclosed in a conventional prior art. The high pressure gas G is conveyed, through a fluid tube A2, to a fluid spraying tube A3 provided at a front end of the spraying gun A, and is sprayed out of the fluid spraying tube A3. A conveying tube A4, which has a cross section area smaller than that of the fluid tube A3, is provided in the fluid tube A3. When the high pressure gas G is spraying out of the fluid tube A3, Venturi effect is induced at an outlet of the conveying tube A4, which effectively makes a spraying liquid L in a container A5 being sprayed out from the spraying gun A through the conveying tube A4.
In order to uniform the spraying distribution, the fluid tube A3 is made to have a bending shape and in rotation when driving. The conveying tube A4 disposed in the fluid tube A3 is made of a flexible material, so as to be deformed by bending with the rotation of the fluid tube A3. Thus, a mixed fluid of the high pressure gas G and spraying liquid L will be spraying uniformly in every direction with the rotation of the fluid tube A3. However, with the increasing time duration in use of the spraying gun A, the conveying tube A4 may wear down due to friction to the fluid tube A3 or may break due to material fatigue, that results in reducing of durability and parts replacement with increasing frequency.